1. Field of the Invention
The present invention relates to a fan frame structure and, more particularly, to a fan frame structure including a plastic casing and a metal fixing frame.
2. Description of the Related Art
FIG. 1 shows a conventional fan frame structure including a frame 10 having a central accommodation space 11 receiving a bottom base 12. Formed at a center of the bottom base 12 is a shaft tube seat 13, allowing mounting of a fan motor and fan blades to the bottom base 12 in the accommodation space 11. A plurality of support arms 14 are interconnected between the bottom base 12 and an inner periphery of the accommodation space 11. The frame 10 is integrally formed with the bottom base 12.
The conventional fan frame structure is integrally formed by die casting with metal such as aluminum or by injection molding with plastic material. Using metal material results in high costs of the fan frame structure. On the other hand, the support arms 14 of the fan frame structure made of plastic material are fragile and, thus, liable to break, leading to problems in structural strength and quality. Furthermore, new molds for the integrally formed fan frame structure of metal or plastic material are required when the size of the bottom base 12 is changed, although the frames 10 of many fans have the same specification. Furthermore, conventional fan frames have various specifications to meet the requirements of assembly of fan motors of differing powers, leading to problems in inventory management due to various types of products or demand of a large warehouse or space
Thus, a need exists for a fan frame structure that can be manufactured at low costs while allowing easy inventory management, saving the costs for molds, and enhancing the quality.